Water-treating compound



Patented Jan. 27, 1942 UNITED STATES PATENT OFFICE WATER-TREATING COMPOUND Cyrus W. Rice, Pittsburgh, Pa.

No Drawing. Application June 15, 1940, Serial No. 340,777

3 Claims.

boilers and heaters which result through depositions of salts that are insoluble under the conditions existing in most heating instrumentalities, have been proposed and employed. The preponderant scale-forming elements present in all waters are calcium and magnesium, which tend under boiler conditions to form insoluble precipitates having the quality of encrusting the surfaces upon which they are deposited. Silica, on the other hand, while present in proportionally much smaller quantities in most water supplies, proves by far the most troublesome water constituent because of its quality of forming dense and adherent encrustationsQ and the property it possesses of cementing chemical precipitates or sludges into hard masses; all of which influences have a direct bearing on boiler repairs and cleaning costs.

My invention relates to a type of treatment in which the inorganic scale-forming and cementing constituents normally present in water react chemically with certain proteins in the formation of salt-like rystalloids, which remain in intiinate suspension 'in the water in its passage through the water-heating and feeding equipment of a boiler, and within the circulating water within boilers themselves, until the crystalloid bodies are removed to waste through means provided for'the purpose.

Thepresmt practices in use for conditioning boiler feed water with commercial chemicals, under the best sorts or treatment control, result in more or less deposition of objectionable sludge materials within water-carrying and heating equipment, and boilers.

.Supplemental treatments employing starches are beneficial in this connection, but have proven uncertain in their effects. This is largely because they function merely mechanically in preventing hard sludge formation, and because of the detructive action soda concentrations and temperv ature within boilers have on the starches. r By using compounds in accordance with my invention, the intimate chemical reaction between reacted proteins of the kind employed and scale-forming and cementing constituents in waters, with resultant formation of amorphous crystalloid compounds, I provide greater protection against hard scale and sludge formations than it is possible to obtain by the mechanical eifects of starch, or similar colloid-producing materials, or by any straight treatment with inorganic chemicals.

The proteins which I employ react chemically with calcium, and magnesium in the formation of calcium and magnesium protein compounds, and have also ability to react with silica.

Being crystalloid, the bodies formed by reaction of each of the scale-forming ingredients with the protein compounds has a specific solubility in water, and the lesser solubility of calcium, magnesium and silica causes these reaction products to exist as colloids with high dispersion value. This gives a control in the conditioning of feed waters that definitely eliminates the possibility of troublesome scale and sludge formations within water heating instrumentalities and in the connections thereto, and permits the scaleinhibiting niaterial to be introduced satisfactorily in the feed water which passes to a boiler. It thus has a general advantage over purely inorganic materials, in that its crystalloid nature, and

the crystalloid nature of its reaction products, accommodates it to the free circulation of water in which it is included.

Briefly to indicate my, invention, I have discovered that suitably reacted proteins are capable of maintaining in a body of water a reactive and adsorptive colloidal dispersion, and that by reaction with calcium and magnesium (also with iron and other metals) such colloidal reagents do not lose their crystalloid character. On the contrary, the compound which are formed by reaction of the ubstances commonly found in boiler water with a protein compound such as I employ are crystalloid and not scale-forming. They are eil'ectively eliminated to waste by boiler blowdowns, or other modes in which freely suspended matter may be removed from 8. containing vessel.

I have recognized that many types of proteins which may be exemplified by casein, glycinin, cottonseed protein, andgluten are remarkably alike, being almost identical incarbon, hydrogen,

oxygen, nitrogen, sulphur, and phosphorous content. They are amphoteric and acquire the ability to 'form stable colloidal solutions when suitably reacted. In preparing my boiler compound, I react the proteins with an acid which, under suitable conditions, will form a stable combination with the protein rather than breaking down the protein into amino acids. Thus, I have found that I may react the amphoteric proteins, such as casein, glycinin, gluten, and cottonseed protein with acids, such as phosphoric acid, lactic acid and citric acid to form stable protein compounds of those acids. Acids such as sulphuric acid, nitric acid, and hydrochloric-acid are not suitable in making my boiler compound, for the reason that they cannot be controlled in reaction with a protein to give the desired stable protein compound.

In reacting the proteins with acids suitable for the purpose of producing protein compounds which are stable as produced, and under boiler conditions, care should be taken that the reac tion conditions are controlled. This is in order to avoid the above-noted decomposition into amino acids which are far less effective in boiler water treatment than the salt-like gels typical of the stable reaction products of proteins and the acids.

The following examples will illustrate suitable reactions producing the colloidal material which I use in water treatment:

Example No.1

These materials are mixed together with agitation to produce a glycinin phosphate, which is a gelled product of the reaction. The reaction will take place at room temperaturawithout the application of heat.

In effecting a straight reaction of a protein, such as the above-noted reaction, between glycinin and orthophosphoric acid of the given H2PO4 value, the protein reacted should not be substantially less than 25% by weight of the reaction mixture, as the water content of orthophosphoric acid tends to break down the glycinin into amino acids, which are much less desirable for water conditioning purposes. The 70% HaP04 value of the orthophosphoric acid is given as exemplary because that is the approximate value of a usual and desirable commercial acid. It is therefore the water content of the orthophosphoric acid which determines the proportion of protein which it is necessary to react with the phosphoric acid, greater H3PO4 value of the acid requiring a lower proportion of a protein, and vice versa.

In the use of lactic acid in the production of my water conditioning agent with glycinin I find that almost any concentration of the acid may be employed without apportioning the percentage of-t-he protein, as for example:

Example No. 2

Parts by weight 85% lactic acid' 56 Glycin-in 44 is as effective in this conversion to the desired colloid as is a mixture of Parts by weight It should be explained that in the case of phosphoric acid, the problem involved is due to the water content of the acid. If there be presto form dextrin which is itself a valuable boilerconditioning substance. The above requirements as to proportions of protein and phosphoric acid and the concentration of acid should therefore be taken with the provision that the use of water-absorbent substances during the reaction, either starch, or starch-like material, which may suitably become a part of the compound, or a material which may be separated from the reaction products, such as clay, greatly broadens the range of both proportion and concentration.

It should, however, be understood that in the absence of a water-absorbent during the reaction by which the boiler compound is 'produced, the less the H3PO4 value of the phosphoric acid used for the reaction, the greater should be the proportion of protein with respect to the acid, in order so to control conditions that decomposition into amino acids is avoided. In the use of citric acid as well as lactic acid, the problem of decomposition is less exacting. The use of phosphorlc acid as the reagent does, however, give certain specific advantage, since its inclusion in a protein compound imparts to that compound the recognized properties of a phosphate in maintaining favorable condition within a boiler or water heater.

It is to be understood that mixtures of proeins may suitablybe subjected to reaction in making my water-conditioning compounds, or

'a plurality of separately reacted proteins may be mixed for use. This is true of gluten, which is less dlspersible' in hot water, and which may desirably be 'mixed with another protein, such as glycinin, for the solubilizing and stabilizing reaction.

As exemplary of a reaction with mixed proteins, we may give the following:

Example N0. 3

Parts by weight Commercial orthophosphoric acid (70% H3PO4) 70 Glycinin 15 Gluten 15 These materials were mixed together with agitationto produce a mixed mass of glycinin phosphate and gluten phosphate as a gelled product of the reaction. The reaction will take place at normal room temperature, without the application of heat.

Inhibition to the deposit of silicates is also effected by the reacted proteins, and by the reaction products which they'form with the main scale-forming radicals in the boiler water. In the boiler or water-heater the colloidal solution of reacted protein reacts with scale-forming radicals to produce a variety of crystalloid compounds, such as calcium glycinate, magnesium glycinate, calcium magnesium glycinate, calcium magnesium phosphate, magnesium glycinin phosphate, calcium magnesium glycinin phosphate, glycinin silicate. Glycinin lactate and glycinin citrate as exemplary of the stable reacted proteins in that they tend to react with calcium and magnesium and in measure with silicon to form crystalloid bodies. None 01' the products of such colloidal reactions are capable of cemented deposition to form hard sludge masses either in feed water heaters, in water-feeding equipment, or in boilers. On the contrary, being themselves crystalloids, they tend on agglomeration to remain in suspension in the water or to be precipitated in the form of a soft sludge which ing it down.

may readily be removed from the boiler by blow- The'stable reacted proteins thus initially react with calcium, magnesium and silica to pre-- made with the acid-reacted proteins, and have equal effect in introducing desirableamorphous crystalloid compounds in boiler waters. Ex amples of such mixtures may be given as follows:

Example No. 4 I Parts by weight Commercial orthophosphoric acid (70% H3PO4) 70 Glycinin 2O Finely divided metallic zinc 5 The reaction product is gelled to a solid state and consists of zinc acid glycinate, or glycinin acid zine phosphate.

Example No. 5

Parts by weight -C0mmercial lactic acid (85% concentration)- 56 Glycinin n 4O Finely divided metallic zinc 4 These materials also may be mixed together at normal room temperature with agitation to give the gelled reaction product. The products containing zinc or aluminum possessthe same general properties as do the simple acid-reacted proteins. I have found that zinc, or its equivalent aluminum, performs a variety of functions through which water may be passed.

If, in reacting to form the water-treating compound the proportions be varied from these given above so that the proportion of acid to protein is carefully increased, the product'ls a heavy liquid colloid, rather than a solid rubber-like mass. This is particularly true if zinc or aluminum is not included in the reaction mixture. If however, the proportion of acid with respect to protein is notexcessive, the product (assuming that lactic acid be used) is nonetheless fundamentally a gel, capable of forming with water a colloidal solution, or fine colloidal dispersion stable under boiler conditions and capable of effecting the desired reactions in a boiler or water heater. It is desirable to produce a treating compound in solid form, because it may in that form be conveniently shipped and stored. It is desirable, as above noted, to react the compound with alkalinity due to sodium, potassium,

or ammonium, before introducing it into the boiler water, unless there be present in the boiler water a substantial alkaline concentration. This is in order to insure against causing a corrosive 4 effect in the boiler.

It should be borne in mind that a great advanmain suspended in the water, and are, therefore,

readily removed by blowdowns to waste. This results in reduced carryovers and better steam .qualities. Whether the boiler reactions are true chemical reactions, :or whether they tend rather -;.'to'be physical reactions of adsorptive kind, or

in making up the water-conditioning compound.

For example in the initial gel-forming reaction it acts as a retardant, reducing the activity of the'acid, such as 'orthophosphoric acid, in decomposing the protein to components of .the,-

It should, however, be borne in mind that with-. out the addition of these metals the treating compound in its simpler form, such as glycinin phosphate, or glycinin lactate, is capable of re-'- with a suitable alkaline reagent, such as a compound of sodium, potassium or ammonium in water solution prior to its introduction into water in, or passing. to, a boiler or water heater. The resultant product, such as. sodium glycinin phosphate or sodium zinc glycinin phosphate forms in the water a true colloidal solution, and is, therefore, capable of being passed through the water connection: without inhibiting any tendtend to the formation of aggregates and micelles, it is a fact that the reacted proteins serve both initially and persistently to prevent scale-forming deposition of calcium and'magnesium, and the cementing action of silicates. Small quantities of the reactedproteins have proven highly effective in destroying the cementing action of silicates in the complex and highly variant scale-' formations' they tend to make with calcium, magnesium, sodium, aluminum and iron.

I claim as my invention:

1. A water-treating compound for boilers and water heaters consisting essentially of a protein- .ate which is the reaction product of a protein selected from the group consisting of casein, glycininrgluten, and cottonseed protein with an acid selected from the group consisting of phosphbric acid, lactic acid, and citric acid, and a metal selected from the group consisting of zinc and aluminum, the said water-treating compound being substantially free of amino decomposition -3. A water-treatingcompound for boilers'and water heaters consisting essentially of gluten phosphate which is the reaction product of gluten with phosphoric acid, the said water-treating compound being substantially free of amino decomposition products of the reacted protein.

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